1. Field of the Invention
The present invention relates to a backlight unit, and more particularly, to a backlight unit having an efficient assembly structure and a liquid crystal display device having the same
2. Description of the Related Art
A liquid crystal display device displays an image using light. The liquid crystal display device does not emit light by itself, and therefore it necessarily requires a backlight unit for generating light.
The backlight unit is classified into an edge type backlight unit or a direct type backlight unit depending on the location of a light source.
FIG. 11 is an exploded perspective view schematically showing a direct type liquid crystal display device in the related art.
Referring to FIG. 11, the related art liquid crystal display device includes a backlight unit 10, a panel guide 60, a liquid crystal panel 70 and a case 80.
The backlight unit 10 includes a bottom cover 11, a reflective sheet 13, first and second lower side frames 15 and 16, first and second common electrodes 18 and 19 each having a plurality of holders, a plurality of lamps 21, first and second upper side frames 23 and 25, an optical sheet 26, first and second inverters 28 and 29, and first and second protective covers 31 and 32.
The reflective sheet 13, the first and second lower side frames 15 and 16, the first and second common electrodes 18 and 19 and the first and second upper side frames 23 and 24 is sequentially seated on the bottom cover 11. Each common electrode 18 and 19 is fixed to the first and second lower side frames 15 and 16. The first and second lower side frames 15 and 16 are fixed to the bottom cover 11 through the reflective sheet 13. The first and second upper side frames 23 and 24 are fixed to the first and second lower side frames 15 and 16, respectively.
As shown in FIG. 12, the plurality of holders 18a and 19a is integrally formed on each of the first and second common electrodes 18 and 19. The lamps 21 are electrically connected to the holders 18a and 19a of the first and second common electrodes 18 and 19.
Wires 28a and 29a of the first and second inverters 28 and 29 are electrically connected to the first and second common electrodes 18 and 19 by using screw, respectively.
The optical sheet 26 is seated on the first and second upper side frames 23 and 24. The panel guide is disposed on the first and second upper side frames. The liquid crystal panel 70 is seated on the panel guide 60. The case 80 is fixed to the bottom cover 11.
The direct type backlight unit is widely used for a medium/large sized liquid crystal display device for displaying a large sized image, since light which is emitted from the respective lamp 21 is directly irradiated to a front.
The related art direct type liquid crystal display device has disadvantages in that the assembly process is complicated because the first and second lower side frames 15 and 16, the first and second common electrodes 18 and 19, and the first and second upper side frames 23 and 24 should be fastened, respectively.
In addition, the related art direct type liquid crystal display device has disadvantages in that a noise of a vibration due to a high driving voltage is generated from the first and second common electrodes 18 and 19 since the first and second common electrodes 18 and 19 are fixed to the first and second lower side frames 15 and 16 by using screw.